The trichloride, IC1 31 results from the action of excess of chlorine on iodine, or from iodic acid and hydrochloric acid, or by heating iodine pentoxide with phosphorus pentachloride.
It is a white powder almost insoluble in water and nitric acid, and when heated, is first converted into metantimonic acid, HSbO 3, and then into the pentoxide Sb205.
Since conhydrine is dehydrated by phosphorus pentoxide into a mixture of a and f3 coniceines, it may be considered an oxyconine.
Phosphorus combines directly with the metal to form W3P4; another phosphide, W2P, results on igniting a mixture of phosphorus pentoxide and tungsten.
Phosphoryl trifluoride, POF3, may be obtained by exploding 2 volumes of phosphorus trifluoride with 1 volume of oxygen (Moissan, 1886); by heating 2 parts of finely-divided cryolite and 3 parts of phosphorus pentoxide (Thorpe and Hambly, Jour.
It burns when heated in air, forming the pentoxide and sulphur dioxide.
Ammonium metavanadate is obtained when the hydrated vanadium pentoxide is dissolved in excess of ammonia and the solution concentrated.
It is also formed by oxidizing bismuth trioxide suspended in caustic potash with chlorine, the pentoxide being formed simultaneously; oxidation and potassium ferricyanide simply gives the tetroxide (Hauser and Vanino, Zeit.
Columbium pentoxide (columbic acid), Cb205, is obtained from columbite, after the removal of tantalum (see above).
Columbium oxysulphide, CbOS 3, is obtained as a dark bronze coloured powder when the pentoxide is heated to a white heat in a current of carbon bisulphide vapour; or by gently heating the oxychloride in a current of sulphuretted hydrogen.